This invention relates to a locking device and, more particularly, to a releasable lock useful in connection with hammers, teeth, chain shackles, etc. Such devices encounter severe wear because of contact with the material being worked, i.e., rock, gravel, ground, kiln material, etc., and thus are subject to accelerated wear particularly in the work engaging surfaces. This has led, over the years, to the provision of two-part devices -- the part encountering the work being replaceable, i.e., hammer, point, chain shackle, etc. Thus, it is essential that the means securing the two parts together be readily removed -- otherwise a valuable piece of equipment may be out of operation for a substantial time.
On the other hand, inasmuch as the work is arduous, it is also essential that the parts be secured together in a rugged, reliable fashion. This has led to the development of a wide variety of different releasable locks.
For example, in the hammer area, as illustrated by co-owned U.S. Pat. No. 3,510,076, a locking pin extended through aligned passages in the two parts, the pin being further immobilized by locking rings at the two ends thereof. In certain instances under harsh working conditions, the rings have failed or otherwise deteriorated so that their stabilizing function, relative to the locking pin, was lost and the parts become inadvertently detached. Depending upon the environment, a detached part could not only be costly in terms of permitting wear of a part not intended to be contacted by the work but actually dangerous to people in the vacinity if the part become detached under conditions where it could fly off of its holder.
The releasable lock of the present invention avoids these drawbacks and reconciles the twin goals of ready releasability while providing a reliable attachment through the use of a deformable rivet extending through a diametral bore in the locking pin securing the two parts together. As such, the inventive arrangement provides substantial advantages over prior approaches employing bore-equipped pins such as U.S. Pat. No. 2,186,047 and 3,022,018.
Other objects and advantages of the invention may be seen in the details of the ensuing specification.